JP2011027771A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device in which even when both ends of a fixing belt are overheated, the fixing belt is hardly deteriorated. <P>SOLUTION: A fixing part 5 presses a fixing roller 150 configured such that part except for both ends of a roller shaft 151 is covered with an elastic layer 152 by a pressure roller 160 via the fixing belt 154, to secure a fixing nip N and heats the fixing belt 154 by electromagnetic induction, while circulating the fixing belt 154, to pass a sheet on which an unfixed image is formed through the fixing nip N and heat-fix the unfixed image. A pair of meandering regulating members 158 have a nearly cylindrical shape with a bottom and are configured so that part of the outer circumferential surface of the fixing belt 154 comes into contact with the inner circumferential surface 157d thereof and the edge of the fixing belt 154 comes into contact with the bottom 157c thereof, to regulate the meandering of the fixing belt 154. A pair of meandering regulating members 158 are disposed at both ends of the fixing roller 150, while coming into contact with the roller shaft 151, respectively. At least, thermal conductivity of the meandering regulating members 158 is higher than that of the elastic layer 152. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electromagnetic induction heating type fixing device and an image forming apparatus using the fixing device, and more particularly to a technique for preventing excessive temperature rise in a non-sheet passing portion of a fixing belt.

An image forming apparatus such as a copying machine forms a fixing nip by pressing a pressure roller against a fixing roller, and an unfixed image such as toner formed on the recording sheet is fixed by passing the recording sheet through the fixing nip. A fixing device is provided.
The fixing roller is heated to melt and fix an unfixed image on a recording sheet, and in recent years, an electromagnetic induction heating type fixing device capable of raising the temperature in a short time is becoming mainstream.

FIG. 6 is a partially cutaway perspective view showing a schematic configuration of such a fixing device.
As shown in the figure, the fixing device 1000 includes a magnetic flux generator 1170, a fixing roller 1150, a fixing belt 1154, a pressure roller 1160, and the like.
The fixing belt 1154 is a cylindrical endless belt including an induction heat generating layer.
The fixing roller 1150 is a driven roller that is inserted into the fixing belt 1154 and has a circumferential surface except for both ends of the roller shaft 1151 covered with an elastic layer 1152.

Further, at both ends of the fixing roller 1150, a hook-like shape that contacts both edges of the fixing belt 1154 and restricts the movement in the direction in which the roller shaft 1151 extends (hereinafter referred to as “roller shaft direction”). A meandering restriction plate 1158 is inserted into the roller shaft 1151.
Similarly, the pressure roller 1160 has a peripheral surface except for both ends of the roller shaft 1161 covered with an elastic layer 1162, is driven to rotate in the direction of the arrow, and presses the fixing roller 1150 via the fixing belt 1154. The fixing nip N is secured.

The magnetic flux generator 1170 is disposed at a position opposite to the pressure roller 1160 with the fixing belt 1154 interposed therebetween, and generates a magnetic flux for generating heat at the induction heating layer of the fixing belt 1154.
In the above configuration, when the magnetic flux is generated from the magnetic flux generator 1170 while the fixing belt 1154 is driven to rotate, the portion of the induction heating layer of the fixing belt 1154 facing the magnetic flux generator 1170 mainly generates heat, and this heat generating portion The temperature reaches the fixing nip N, the temperature of the fixing nip N is raised to a temperature suitable for fixing, and when the toner image formed on the recording sheet S passes through the fixing nip N, the recording is performed by heating and pressing. Heat-fixed on the sheet S.

JP 2004-198969 A

  However, when the heat fixing is performed, the fixing belt 1154 is deprived of heat by the recording sheet S at the central portion in contact with the recording sheet S, but the temperature is lowered. In the portion (hereinafter referred to as “non-sheet passing portion P”), the temperature remains high without being deprived of heat, so that the central portion of the fixing belt 1154 is set to the target temperature and the magnetic flux generating portion 1170 is contacted. When power is supplied, the temperature of the non-sheet passing portion P further increases.

As a result, at both ends of the fixing belt 1154, the elastic layer included in the fixing belt 1154 is heated to a temperature equal to or higher than the heat resistance temperature, so that the characteristics are rapidly deteriorated, cracks and the like are generated, and the fixing quality is deteriorated. is there.
The present invention has been made in view of the above problems, and a fixing device in which deterioration of the fixing belt 1154 does not easily occur even when both ends of the fixing belt 1154 tend to rise in temperature compared to the central portion, and the fixing device. An object of the present invention is to provide an image forming apparatus provided with a fixing device.

  In order to achieve the above object, the fixing device according to the present embodiment is arranged inside the loop path of the endless belt, and a portion excluding both ends of the metallic roller shaft is covered with an elastic member. The first roller is pressed by the second roller through the belt from the outer circumference of the belt to secure a fixing nip between the belt surface and the second roller, and the belt is circulated while A fixing device that heats by induction and passes a sheet on which an unfixed image is formed, through the fixing nip, and thermally fixes the unfixed image. It is a bottomed cylindrical shape, and a part of the outer peripheral surface of the belt is in contact with the inner surface of the cylindrical portion and the belt edge is in contact with the bottom of the cylindrical portion to regulate the meandering of the belt. A pair of belt regulating members Serial roller shaft is disposed in a state in contact with the belt regulating member is characterized by high thermal conductivity than at least the elastic member.

In the above configuration, even if both ends of the fixing belt are induction-heated, heat at both ends of the fixing belt can be released to the roller shaft via the belt regulating member having high thermal conductivity. The temperature rise in the non-sheet passing portion is suppressed, and the fixing belt is hardly deteriorated.
In addition, when viewed from the axial direction of the first roller, it is desirable that the belt regulating member is in contact with the belt over two thirds or more of the inner circumference of the cylindrical portion.

As a result, a large amount of heat can be released from the fixing belt to the roller shaft.
Further, the belt regulating member has a bottomed cylindrical shape, and an inner diameter of the cylindrical portion is larger than an outer diameter of the belt, and the difference is within a range of 0.1 mm or more and 0.3 mm or less. Good.
Further, the belt includes a metal layer heated by electromagnetic induction and other layers, and the outer peripheral surface of the metal layer is exposed at both end portions, and the inner surface of the side surface portion is formed of the metal layer. It is desirable to make contact with the outer peripheral surface.

As a result, the belt regulating member can be in direct contact with the metal layer that is the heat generation source, so that heat at both ends of the metal layer can be released to the roller shaft more efficiently.
Further, when viewed from a direction orthogonal to the axial direction of the first roller, the total length of the portions where the inner surface of the side surface portion and the outer peripheral surface of the metal layer are in contact is effectively determined from the width of the belt. It may be less than or equal to the value obtained by reducing the paper width.

Furthermore, the belt regulating member may be formed by joining a first member that contacts the roller shaft and a second member that contacts the belt.
In this case, the second member is preferably made of a paramagnetic stainless material, and the first member is preferably made of a material containing aluminum, copper, or silver.
The belt regulating member may be made of a resin material to which a metal compound is added.

  Note that the present invention may be an image forming apparatus including the fixing device.

1 is a schematic cross-sectional view of a tandem color digital printer according to an embodiment of the present invention. FIG. 3 is a partial cross-sectional perspective view of a fixing unit according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of an end portion of the fixing roller, the fixing belt, and the pressure roller according to the embodiment of the present invention. It is a perspective view of the meandering control member which concerns on embodiment of invention. It is a figure which shows the modification of the fixing | fixed part which concerns on embodiment of this invention. It is a perspective view which shows the conventional fixing part.

Hereinafter, an embodiment of an image forming apparatus according to the present invention will be described by taking as an example a case where it is applied to a tandem type color digital printer (hereinafter simply referred to as “printer”).
FIG. 1 is a schematic cross-sectional view showing the overall configuration of the printer 1.
As shown in the figure, the printer 1 includes an image processing unit 3, a paper feeding unit 4, a fixing unit 5, and a control unit 60. The printer 1 is connected to a network (for example, a LAN) and is connected to an external terminal device (not connected). When a print job execution instruction is received from (shown), a toner image composed of yellow, magenta, cyan, and black is formed based on the instruction, and a full-color image is formed by multiple transfer of these. Hereinafter, the reproduction colors of yellow, magenta, cyan, and black are represented as Y, M, C, and K, and Y, M, C, and K are added as subscripts to the numbers of the components related to the reproduction colors.
<Image process part>
The image processing unit 3 includes image forming units 3Y, 3M, 3C, and 3K corresponding to each of Y to K colors, an optical unit 10, an intermediate transfer belt 11, and the like.

The image forming unit 3Y includes a photosensitive drum 31Y, a charger 32Y, a developing unit 33Y, a primary transfer roller 34Y, a cleaner 35Y for cleaning the photosensitive drum 31Y, and the like disposed around the photosensitive drum 31Y. A Y-color toner image is formed on the drum 31Y. The other image forming units 3M to 3K have the same configuration as the image forming unit 3Y, and the reference numerals are omitted in FIG.
The intermediate transfer belt 11 is an endless belt, is stretched around a driving roller 12 and a driven roller 13, and is driven to rotate in the direction of arrow A.

The optical unit 10 includes a light emitting element such as a laser diode, emits a laser beam L for forming an image of Y to K colors by a drive signal from the control unit 60, and exposes and scans the photosensitive drums 31Y to 31K.
By this exposure scanning, electrostatic latent images are formed on the photosensitive drums 31Y to 31K charged by the chargers 32Y to 32K. The electrostatic latent images are developed by developing units 33Y to 33K, and Y to K color toner images are superimposed on the same positions on the intermediate transfer belt 11 and primarily transferred onto the photosensitive drums 31Y to 31K. It is executed at different timings.

The toner images of the respective colors are sequentially transferred onto the intermediate transfer belt 11 by the electrostatic force acting on the primary transfer rollers 34Y to 34K to form a full-color toner image, and further move toward the secondary transfer position 46.
On the other hand, the paper feed unit 4 includes a paper feed cassette 41 that stores the recording sheets S, a feed roller 42 that feeds the recording sheets S in the paper feed cassette 41 one by one onto the transport path 43, and a fed recording sheet S. Are provided with a timing roller pair 44 for taking the timing of feeding the toner to the secondary transfer position 46, and the recording sheet S is transferred from the paper feeding unit 4 to the secondary transfer position in accordance with the movement timing of the toner image on the intermediate transfer belt 11. The toner images on the intermediate transfer belt 11 are collectively transferred onto the recording sheet S by the action of the secondary transfer roller 45.

The recording sheet S that has passed the secondary transfer position 46 is conveyed to the fixing unit 5, and the toner image (unfixed image) on the recording sheet S is fixed to the recording sheet S by heating and pressurization in the fixing unit 5. Thereafter, the sheet is discharged onto the discharge tray 72 via the discharge roller pair 71.
<Fixing part>
FIG. 2 is a partial cross-sectional perspective view of the fixing unit 5.

As shown in the figure, the fixing unit 5 includes a fixing roller 150, a fixing belt 154, a meandering regulating member 158, a pressure roller 160, an induction coil unit 170, and the like.
Details of each part will be described below.
<Induction coil unit>
The induction coil unit 170 generates an alternating magnetic field toward the fixing roller 150, and includes a lower casing portion 171, a side magnetic core 172, an induction coil 173, a main magnetic core 174, a center magnetic core 174a, and It consists of an upper casing part 175.

The lower casing portion 171 is made of an insulating material such as resin, and an annular groove portion around which the induction coil 173 is wound is provided.
The side magnetic core 172 is a long member made of a ferromagnetic material, and is disposed in parallel to the roller shaft along the respective inner walls of the lower casing portion 171 on the Y direction side and the Y ′ direction side. Yes.

The induction coil 173 is a litz wire and is covered with a heat resistant resin (not shown).
The induction coil 173 is connected to a high-frequency inverter (not shown), and generates an alternating magnetic field having a predetermined frequency by supplying high-frequency power of 10 to 100 [kHz] and 100 to 2000 [W], and fixing. The roller 150 is heated.
The main magnetic core 174 is made of a ferromagnetic material and is an arch-shaped member provided across the two side magnetic cores 172.

The upper casing portion 175 is made of an insulating material such as resin, and serves to cover the lower casing portion 171 that houses the side magnetic core 172, the induction coil 173, and the main magnetic core 174.
<Pressure roller>
As shown in FIG. 2, the pressure roller 160 includes a roller shaft 161 and an elastic layer 162.

The roller shaft 161 is, for example, a hollow shaft such as aluminum having an outer diameter of 30 mm and a thickness of 3 mm, and is driven to rotate by a drive mechanism (not shown).
The elastic layer 162 is a cylindrical body made of silicone sponge rubber.
<Fixing roller>
The fixing roller 150 includes a roller shaft 151 and an elastic layer 152 as shown in FIG.

The roller shaft 151 is a cylindrical metal pipe, and both ends thereof are supported by bearings (not shown).
More specifically, the roller shaft 151 is a solid shaft made of a material having excellent thermal conductivity such as aluminum having an outer diameter D1 of 16 mm.
The elastic layer 152 is a sponge made of silicone rubber having high elasticity and high heat insulation, and is provided so as to cover portions excluding both ends of the roller shaft 151 to be supported.
<Fixing belt>
The fixing belt 154 is formed by laminating an induction heat generating layer 154a, an elastic layer 154b, and a release layer 154c in this order.

The induction heating layer 154a is made of a metal such as nickel having a thickness of 40 μm and high magnetic permeability, for example.
The elastic layer 154b is made of, for example, silicone rubber having a thickness of 200 μm.
The release layer 154c has a thickness of 30 μm, for example, and is made of a resin material having excellent release properties such as PFA.

FIG. 3 is a cross-sectional view of the vicinity of the ends of the fixing roller 150, the fixing belt 154, and the pressure roller 160.
In the drawing, only the configuration of one end of the both ends of the fixing roller 150 is shown, but the other end not shown is also the same as the configuration shown.
As shown in the figure, the fixing belt 154 has a configuration in which the outer peripheral surface of the induction heating layer 154a is exposed in a range in which the length is L2 mm or less from the tip of each end.

That is, when the length of the induction heating layer 154a in the roller axis direction is L1, the width of the elastic layer 154b and the release layer 154c, that is, the width of the portion of the fixing belt 154 that contributes to fixing (effective sheet passing width) is L1-2 × L2 mm.
<Meandering restriction member>
FIG. 4 is an external perspective view of the meandering restricting member 158.

As shown in the figure, the meandering restricting member 158 is a substantially bottomed cylindrical member, and includes a first member 156 and a second member 157.
The first member 156 is provided with a cylindrical portion 156a having an inner diameter D2 of 15.8 mm, for example, by burring or the like at the center of the disk-shaped member, and has a higher thermal conductivity than the second member 157. For example, it is made of aluminum, copper, silver or the like.

As shown in the figure, the cylindrical portion 156a is provided with a notch portion 156b at a position where the outer periphery of the cylindrical portion is divided into three equal portions of 120 °.
The end of the roller shaft 151 of the fixing roller 150 is press-fitted into the cylindrical portion 156a.
The notch 156b is for facilitating the press-fitting by making the cylindrical part 156a easy to deform along with the press-fitting.

As shown in FIG. 3, the second member 157 is a bottomed cylindrical member having a through hole 157 a at the center, is not a ferromagnetic material, and has high mechanical strength, such as SUS (stainless steel). Steel) 304 or the like.
Thus, the reason why the strength of the second member 157 is increased is to prevent the second member 157 from being worn when the second member 157 and the induction heating layer 154a come into contact with each other.

On the other hand, since the first member 156 does not come into contact with the fixing belt 154, mechanical strength is not required so much, and a metal having higher thermal conductivity is used as described above. Moreover, since it is separated from the induction coil unit 170, the kind of magnetism does not matter.
Note that the second member 157 is made of a material having higher thermal conductivity than at least the elastic layer 152.

The cylindrical portion 157b of the second member 157 has a height L3 from the bottom surface 157c in the roller axis direction of 10 mm.
The inner peripheral surface 157d of the cylindrical portion 157b is in contact with the end portion of the outer peripheral surface of the induction heat generating layer 154a.
As described above, the reason why the second member 157 is made of a material other than a ferromagnetic material is to prevent the magnetic flux generated from the induction coil unit 170 from converging on the second member 157 and to prevent the second member 157 from generating heat. It is.

Further, it is desirable that the first member 156 and the second member 157 be joined using a joining method such as friction welding that can increase the contact area between the two members.
In the above configuration, when the magnetic flux is generated from the magnetic flux generator 170 while the fixing belt 154 is driven to rotate, the portion of the induction heating layer of the fixing belt 154 facing the magnetic flux generator 170 mainly generates heat. The temperature reaches the fixing nip N, the temperature of the fixing nip N is raised to a temperature suitable for fixing, and when the toner image formed on the recording sheet S passes through the fixing nip N, the recording is performed by heating and pressing. Heat-fixed on the sheet S.

  At this time, in the central portion where the fixing belt 154 is in contact with the recording sheet S, the recording sheet S is deprived of heat and the temperature is lowered, but at both ends where the recording sheet S does not pass, that is, in the non-sheet passing portion, Since the temperature remains high without being deprived of heat, when electric power is supplied to the magnetic flux generator 170 in order to adjust the central portion of the fixing belt 154 to the target temperature, the temperature at both ends tends to further increase.

  In the fixing unit 5 of the present embodiment, the inner peripheral surface 157d of the meandering regulating member 158 is in contact with the outer peripheral surface at the end of the induction heating layer 154a. And the bottom surface 157c of the meandering restricting member 158 is moved to the edge of the induction heating layer 154a about to move in the roller axis direction. By contact, meandering of the fixing belt 154 in the roller axial direction can be suppressed.

Thereby, in the fixing belt 154, excessive temperature rise in the non-sheet passing portions at both ends is prevented, and deterioration of the fixing belt 154 can be prevented.
However, in the nip portion N and the vicinity thereof, as shown in FIG. 3, the elastic layer 152 of the fixing roller 150 is pressed by the pressure roller 160 and dented in the direction of the roller shaft 151. A portion Q where 157d and the outer peripheral surface of the induction heating layer 154a do not contact each other is generated.

The range of the portion where the contact does not occur is desirably less than one third of the circumference of the cylindrical portion 157b when the cylindrical portion 157b is viewed from the roller axis direction.
In other words, the inner peripheral surface 157d of the meandering restricting member 158 and the outer peripheral surface of the induction heat generation layer 154a are in surface contact with each other at two-thirds or more of the circumference of the cylindrical portion 157b.
<Others>
(1) In the printer 1 of the above embodiment, the second member 157 of the meandering restricting member 158 is a bottomed cylindrical member, but is not limited to a complete cylindrical shape as long as it is circular. .

For example, the second member 157 may have a configuration in which notches are provided in some places in the cylindrical portion 157b. Furthermore, the cylindrical portion 157b is not a true cylinder, but has a polygonal shape when viewed from the roller axial direction. It may be.
Even in such a shape, the inner surface of the cylindrical portion 157b and the outer peripheral surface of the end portion of the induction heating layer 154a can be intermittently brought into surface contact, so that heat is released from the conventional case where the surface contact is not made. be able to.
(2) Further, the meandering restricting member 158 has a second member 157 having a higher thermal conductivity than at least the elastic layer 152 and having a strength other than a ferromagnetic material, and a first member having a higher thermal conductivity than this. However, the present invention is not limited to such a two-piece configuration.

For example, as long as there is a member that is paramagnetic, high in strength, and high in thermal conductivity, it is needless to say that it may be constituted by one member.
Further, although the meandering restricting member 158 is made of metal in order to improve wear resistance, it is also possible to use a material other than metal, for example, heat conduction such as a heat resistant resin to which an aluminum compound is added. You may comprise with the material excellent in the property and the moldability.

Thereby, while ensuring high heat conductivity, a meandering control member is not induction-heated.
In addition, as long as the material used for the meandering restricting member has at least thermal conductivity higher than that of the elastic layer 152, the cooling effect of the non-sheet passing portion can be obtained as compared with the conventional case.
(3) In the above embodiment, the length of the part where the outer peripheral surface of the induction heat generating layer 154a is exposed at both ends of the fixing belt 154 is set to the same length as L2 mm. It is not limited to.

For example, when one end of the both ends of the fixing belt 154 is more easily heated than the other end due to variations in the magnetic flux density in the roller axis direction, the induction heating layer 154a on the side that is easily heated It is good also as a structure which further accelerates | stimulates heat dissipation by making the length of the part which outer peripheral surface is exposed longer than the other edge part.
(4) The fixing unit 5 of the printer 1 of the above embodiment is configured so that the inner diameter of the fixing belt 154 and the outer diameter of the fixing roller 150 are substantially the same, and there is almost no gap between the fixing belt 154 and the fixing roller 150. Although a configuration that does not occur has been described as an example, the configuration is not limited to such a configuration.

For example, the inner diameter of the fixing belt is made sufficiently larger than the outer diameter of the fixing roller, and the contact portion between the fixing belt and the fixing roller is reduced only to the nip portion and its peripheral portion. The heat thus applied may be applied to a so-called loose-fitting type fixing unit that prevents the heat from escaping to other members as much as possible.
FIGS. 5A and 5B are diagrams showing the configuration of such a loose-fitting type fixing unit.

As shown in the figure, the fixing device 200 includes a fixing belt 254, a fixing roller 250, a pressure roller 260, a magnetic flux generator 170, a meandering restricting member 258, and the like. In the figure, the fixing belt 254 is in a stationary state.
The fixing belt 254 is a cylindrical elastically deformable belt including an induction heat generating layer 254a, an elastic layer 254b, and a release layer 254c, and is the same as the fixing belt 154 in the above embodiment except for the inner diameter.

The fixing roller 250 has the same configuration as that of the fixing roller 150 in the above-described embodiment, and is arranged on the inner side of the circulation path of the fixing belt 254.
The pressure roller 260 has the same configuration as that of the pressure roller 160 in the above-described embodiment, and is arranged outside the circulation path of the fixing belt 254. The pressure roller 260 presses the fixing roller 250 via the fixing belt 254, and the fixing nip N is formed. Secure. The pressure roller 260 receives a driving force from a driving motor (not shown) and rotates in the direction of the arrow. The driving force is transmitted to the fixing roller 250 and the fixing belt 254, so that the fixing roller 250 and the fixing belt 254 are driven to rotate.

The magnetic flux generator 170 is disposed at a position facing the pressure roller 260 with the fixing belt 254 interposed therebetween.
The meandering restricting member 258 is the same as the meandering restricting member 158 in the above-described embodiment except that the size is different.
That is, the members corresponding to the first member 156 and the second member 157 are the first member 256 and the second member 257, respectively, which are also in a corresponding relationship, and only the dimensions are different.

  The meandering restricting member 258 configured as described above is generated at the end portion of the induction heat generating layer 154a when the inner peripheral surface 257d of the second member 257 contacts the outer peripheral surface of the end portion of the induction heat generating layer 154a. The heat is released to the roller shaft 251 of the fixing roller 250 through the meandering restricting member 258, and the bottom surface 257c comes into contact with the edge of the induction heating layer 154a to move in the roller axis direction. Meandering can be suppressed.

Thereby, in the fixing belt 154, both ends (non-sheet passing portions) are suppressed from being overheated abnormally compared to the center portion, and deterioration of the fixing belt 154 can be prevented.
However, in the nip portion N and the vicinity thereof, as shown in FIG. 3, the elastic layer 152 of the fixing roller 150 is pressed by the pressure roller 160 and dented in the direction of the roller shaft 151, so that the inner peripheral surface 157d of the cylindrical portion 157b. And a portion where the outer peripheral surface of the end portion of the induction heating layer 154a is not in contact with each other is generated.

(5) In the above embodiment, the induction heat generating layer 154a of the fixing belt 154 is longer in the roller axial direction than the elastic layer 154b and the release layer 154c, and the outer peripheral surface is exposed at both ends of the fixing belt 154. However, it is not limited to such a configuration.
For example, even if the induction heat generation layer 154a, the elastic layer 154b, and the release layer 154c all have the same length in the roller axial direction, and the outer peripheral surface of the induction heat generation layer 154a is not exposed at both ends of the fixing belt 154, the elasticity Since the layer 154b and the release layer 154c are thin, even if both of these layers are interposed between the induction heat generation layer 154a and the meandering restriction member 258, the heat is appropriately released from the induction heat generation layer 154a to the meandering restriction member 258. be able to.

This also applies to the fixing belt 254 in the modification (4), and therefore it is not always necessary to expose the outer periphery of the induction heating layer 254a at both ends of the fixing belt 254.
(6) Although the tandem color printer has been described in the above embodiment, the present invention is not limited to this, and is applicable to all image forming apparatuses including an induction heating type fixing device. is there.

  Further, the contents of the above embodiment and the above modification may be combined.

  The present invention can be widely applied to a fixing device and an image forming apparatus using the same.

DESCRIPTION OF SYMBOLS 1 Printer 3 Image process part 3Y, 3M, 3C, 3K Image creation part 4 Paper feed part 5 Fixing part 10 Optical part 11 Intermediate transfer belt 12 Drive roller 13 Driven roller 31 Photoreceptor drum 32 Charger 33 Developer 34 Primary transfer roller 35 Cleaner 41 Paper Feed Cassette 42 Roller 43 Conveying Path 44 Timing Roller Pair 45 Secondary Transfer Roller 46 Secondary Transfer Position 60 Control Unit 71 Discharge Roller Pair 72 Discharge Tray 150 Fixing Roller 151 Roller Shaft 151a Both Ends 152 Elastic Layer 154 Fixing Belt 154a Induction heating layer 154a Induction heating layer 154b Elastic layer 154c Release layer 156 Member 156a Cylindrical portion 156b Notch portion 157 Member 157a Through hole 157b Cylindrical portion 157b Cylindrical portion 157c Bottom surface 157d Inner circumferential surface 158 160 Pressure roller 161 Roller shaft 162 Elastic layer 170 Magnetic flux generator 170 Inductive coil unit 172 Side magnetic core 173 Inductive coil

Claims (10)

A first roller, which is disposed inside the endless belt circulation path and is covered with an elastic member except for both ends of the metallic roller shaft, passes from the outside of the belt rotation path to the belt. The second roller is pressed to secure a fixing nip between the belt surface and the second roller, and is heated by electromagnetic induction while circling the belt, whereby the sheet on which the unfixed image is formed is A fixing device that performs thermal fixing of the unfixed image through a fixing nip,
Both ends of the first roller in the axial direction are substantially bottomed cylindrical, and a part of the outer peripheral surface of the belt is in contact with the inner surface of the cylindrical portion and the edge of the belt is at the bottom of the cylindrical portion. A pair of belt regulating members that regulate the meandering of the belt by contacting the parts are arranged in contact with the roller shaft;
The fixing device according to claim 1, wherein the belt regulating member has higher thermal conductivity than at least the elastic member.   2. The fixing according to claim 1, wherein when viewed from the axial direction of the first roller, the belt regulating member is in contact with the belt over two thirds or more of the inner circumference of the cylindrical portion. apparatus. The belt regulating member has a bottomed cylindrical shape,
2. The fixing device according to claim 1, wherein an inner diameter of the cylindrical portion is larger than an outer diameter of the belt, and a difference thereof is in a range of 0.1 mm or more and 0.3 mm or less. The belt includes a metal layer heated by electromagnetic induction and other layers, and the outer peripheral surface of the metal layer is exposed at both ends.
The fixing device according to claim 1, wherein an inner surface of the side surface portion is in contact with an outer peripheral surface of the metal layer.   When viewed from the direction perpendicular to the axial direction of the first roller, the total length of the portions where the inner surface of the side surface portion and the outer peripheral surface of the metal layer are in contact with each other is the effective sheet passing width based on the belt width. The fixing device according to claim 4, wherein the fixing device is equal to or less than a reduced value.   The fixing device according to claim 1, wherein the belt regulating member is formed by joining a first member that contacts the roller shaft and a second member that contacts the belt.   The fixing device according to claim 6, wherein the second member is made of a paramagnetic stainless material.   The fixing device according to claim 7, wherein the first member is made of a material containing aluminum, copper, or silver.   6. The fixing device according to claim 1, wherein the belt regulating member is made of a resin material to which a metal compound is added.   An image forming apparatus comprising the fixing device according to claim 1.

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